FOSSIL KEPTILES. 329 



thirteen vertebrae are reckoned in it. The faculty which the 

 animal, without doubt, possessed of flying, and the difficulty 

 under which it laboured of creeping or walking, by reason of 

 the disproportioned length of the head and neck, are probably 

 the reasons why a long tail was not necessary for it. 



Though the shoulders and sternum were not very well pre- 

 served, M. Cuvier could ascertain in them all the true charac- 

 ters of the reptile. The same may be said of the bones of the 

 carpus and metacarpus. 



There are, at first, three small toes, one with two phalanges, 

 and one with three. The last phalanx in both is unguical, 

 compressed, hooked, and pointed. The third has three pha- 

 langes ; and as it was mutilated, it probably had a fourth, which 

 was unguical. These numbers are exactly those of the first 

 three toes in crocodiles and lizards. 



Finally, comes the toe, enormously elongated into a thin 

 stem, which eminently characterizes the animal. It has four 

 articulations without a claw. The fourth toe of lizards 

 would have five articulations with a claw. In the crocodiles 

 there are four and no claw, but not this extraordinary 

 elongation. 



The crocodiles and lizards have a fifth toe besides, which 

 in the hzards has four articulations, and in the crocodile but 

 three without a claw. It appears that, in the fossil animal, 

 there remains but a vestige of the fifth toe very obscure. The 

 great toe is probably the fourth, for it is the fourth which is 

 longest in the lizards. The three others precede it in the in- 

 verse order of the number of their articulations. 



To complete the resemblance, the penultimate phalanx is 

 the longest. That which precedes it in the third toe is the 

 shortest, absolutely the same as in the lizards. 



The form of the unguical phalanges is also the same, that of 

 a semi-crescent, compressed, trenchant, and pointed. 



It is scarcely possible to doubt that this long toe served to 

 support a membrane over the entire length of the fore-leg, 



